Abstract : A research effort was carried out with the aim of acquiring a better understanding of the processes leading to the detection of x rays in silicon and germanium, as well as in alkali halide scintillation crystals. Results of this research, as well as of the work of other groups, new enables one to make a comparison of detectors for high resolution nondispersive x-ray analysis, and to draw some conclusions concerning what to expect in the future. The present article is limited to a discussion of resolution in the x-ray energy region. This region spans the energy range from about 1 keV to 100 keV. This in turn corresponds to the wavelength region extending from about 10 Angstroms down to about 0.1 Angstroms.